On top of that, when criminals in Norway leave prison, they stay out. It has one of the lowest recidivism rates in the world at 20%. The US has one of the highest: 76.6% of prisoners are re-arrested within five years.

Norway also has a relatively low level of crime compared to the US, according to the Bureau of Diplomatic Security. The majority of crimes reported to police there are theft-related incidents, and violent crime is mostly confined to areas with drug trafficking and gang problems.

Based on that information, it's safe to assume Norway's criminal justice system is doing something right. Few citizens there go to prison, and those who do usually go only once. So how does Norway accomplish this feat? The country relies on a concept called "restorative justice," which aims to repair the harm caused by crime rather than punish people. This system focuses on rehabilitating prisoners.

Take a look at Halden Prison, and you'll see what we mean. The 75-acre facility maintains as much "normalcy" as possible. That means no bars on the windows, kitchens fully equipped with sharp objects, and friendships between guards and inmates. For Norway, removing people's freedom is enough of a punishment.

Like many prisons, Halden seeks to prepare inmates for life on the outside with vocational programs: woodworking, assembly workshops, and even a recording studio.

The recording studio at Halden prison.YouTube/John StarkAs Bastoy prisoner governor Arne Wilson, who is also a clinical psychologist, explained to The Guardian:

In closed prisons we keep them locked up for some years and then let them back out, not having had any real responsibility for working or cooking. In the law, being sent to prison is nothing to do with putting you in a terrible prison to make you suffer. The punishment is that you lose your freedom. If we treat people like animals when they are in prison they are likely to behave like animals. Here we pay attention to you as human beings.

All of these characteristics are starkly different from America's system. When a retired warden from New York visited Halden, he could barely believe the accommodations. "This is prison utopia," he said in a documentary about his trip. "I don't think you can go any more liberal — other than giving the inmates the keys."

In general, prison should have five goals, as described by criminologist Bob Cameron: retribution, incapacitation, deterrence, restoration, and rehabilitation. In his words though, "Americans want their prisoners punished first and rehabilitated second."

Norway adopts a less punitive approach than the US and focuses on making sure prisoners don't come back. A 2007 report on recidivism released by the US Department of Justice found that strict incarceration actually increases offender recidivism, while facilities that incorporate "cognitive-behavioral programs rooted in social learning theory" are the most effective at keeping ex-cons out of jail.

The maximum life sentence in Norway shows just how serious the country is about its unique approach. With few exceptions (for genocide and war crimes mostly), judges can only sentence criminals to a maximum of 21 years. At the end of the initial term, however, five-year increments can be added onto to the prisoner's sentence every five years, indefinitely, if the system determines he or she isn't rehabilitated.

Anders Breivik. AP

That's why Norwegian extremist Anders Behring Breivik, who killed 77 people in a bombing and mass shooting, was only sentenced to 21 years. Most of the outrage and incredulity over that sentence, however, came from the US.

Overall, Norwegians, even some parents who lost children in the attack, seemed satisfied with the sentence, The New York Times reported. Still, Breivik's sentence, as is, put him behind bars for less than 100 days for every life he took, as The Atlantic noted. On the other hand, if the system doesn't determine Breivik "rehabilitated," he could stay in prison forever.

To those working within Norway's prison system, the short sentences and somewhat luxurious accommodations make complete sense. As Are Hoidel, Halden Prison's director, puts it: "Every inmates in Norwegian prison are going back to the society. Do you want people who are angry — or people who are rehabilitated?"